1. Field of the Invention
The present invention relates generally to medical devices and methods and more particularly to methods and devices for placing stents adjacent a vascular ostium in the peripheral vasculature.
The treatment of occlusions near side branches in a patient's vasculature have been problematic. While stents may be used to maintain patency in the main lumen, the ostium of the side branch is often occluded.
Congenital narrowing of the left common iliac vein due to pressure from the overlying artery is called May-Thurner syndrome and can lead to deep vein thrombosis of the left leg. The blood coming from the legs flows through the deep veins of the legs and the pelvis into the big abdominal vein and then to the heart Normally, the artery which runs to the right leg (right common iliac artery) lies on top of the vein coming from the left leg (left common iliac vein). This close proximity leads, in some people, to pressure of the artery onto the vein and to varying degrees of narrowing of the vein which is characteristic of May-Thurner syndrome. Mild and moderate degrees of narrowing are typically asymptomatic. More severe degrees can lead to obstruction of blood flow from the leg and thus to leg swelling and pain. The narrowed vein can also clot, resulting in left leg deep vein thrombosis (DVT). Several surgical treatment strategies have been employed in the past including venous bypass surgery of the narrowed area, cutting of the iliac artery and repositioning of the artery behind the iliac vein, and construction of a tissue sling or flap to lift it off the iliac vein, but none have fully addressed the condition.
Thus, it is desirable to provide more effective and less invasive methods and systems for treating an occluded ostium in the peripheral vasculature, particularly in patients suffering from May-Thurner syndrome.
2. Description of the Background Art
Flared and other stents for positioning in bifurcation are described in US2007/0073388; US2007/0038283; US2006/0265041; US2006/0106455; US2006/0058864; US2004/0093058; U.S. Pat. No. 7,147,658; U.S. Pat. No. 7,105,015; U.S. Pat. No. 5,749,890; and U.S. Pat. No. 5,632,762.